<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title></title>
        <script src="jquery.js" type="text/javascript" 
        language="javascript"></script>
        
        <script>
        $(document).ready(function()
        {
           $('#troca').click(function()
           {
                
                $.post("ajax1.php", {estado:$('#estado').val()},
		function(data){
                    $('#trocando').html(data);
                }
		 , "html");
        
        
                //$('#trocando').html("MUDOU");
           });
        });
        
        </script>
    </head>
    <body>
        <div id="trocando">Vai trocaaar</div>
        <select id="estado">
            <option>selecione</option>
             <option value="RS">RS</option>
              <option value="SC">SC</option>
        </select>
        <input type="button" id="troca" value="troca"/>
    </body>
</html>
